PMID- 21158293
OWN - NLM
STAT- MEDLINE
DCOM- 20110113
LR  - 20240518
IS  - 0094-2405 (Print)
IS  - 0094-2405 (Electronic)
IS  - 0094-2405 (Linking)
VI  - 37
IP  - 11
DP  - 2010 Nov
TI  - Thoracic target volume delineation using various maximum-intensity projection 
      computed tomography image sets for radiotherapy treatment planning.
PG  - 5811-20
AB  - PURPOSE: Four-dimensional computed tomography (4D-CT) is commonly used to account 
      for respiratory motion of target volumes in radiotherapy to the thorax. From the 
      4D-CT acquisition, a maximum-intensity projection (MIP) image set can be created 
      and used to help define the tumor motion envelope or the internal gross tumor 
      volume (iGTV). The purpose of this study was to quantify the differences in 
      automatically contoured target volumes for usage in the delivery of stereotactic 
      body radiation therapy using MIP data sets generated from one of the four 
      methods: (1) 4D-CT phase-binned (PB) based on retrospective phase calculations, 
      (2) 4D-CT phase-corrected phase-binned (PC-PB) based on motion extrema, (3) 4D-CT 
      amplitude-binned (AB), and (4) cine CT built from all available images. METHODS: 
      MIP image data sets using each of the four methods were generated for a cohort of 
      28 patients who had prior thoracic 4D-CT scans that exhibited lung tumor motion 
      of at least 1 cm. Each MIP image set was automatically contoured on commercial 
      radiation treatment planning system. Margins were added to the iGTV to observe 
      differences in the final simulated planning target volumes (PTVs). RESULTS: For 
      all patients, the iGTV measured on the MIP generated from the entire cine CT data 
      set (iGTVcine) was the largest. Expressed as a percentage of iGTVcine, 4D-CT iGTV 
      (all sorting methods) ranged from 83.8% to 99.1%, representing differences in the 
      absolute volume ranging from 0.02 to 4.20 cm3; the largest average and range of 
      4D-CT iGTV measurements was from the PC-PB data set. Expressed as a percentage of 
      PTVcine (expansions applied to iGTVeine), the 4D-CT PTV ranged from 87.6% to 
      99.6%, representing differences in the absolute volume ranging from 0.08 to 7.42 
      cm3. Regions of the measured respiratory waveform corresponding to a rapid change 
      of phase or amplitude showed an increased susceptibility to the selection of 
      identical images for adjacent bins. Duplicate image selection was most common in 
      the AB implementation, followed by the PC-PB method. The authors also found that 
      the image associated with the minimum amplitude measurement did not always 
      correlate with the image that showed maximum tumor motion extent. CONCLUSIONS: 
      The authors identified cases in which the MIP generated from a 4D-CT sorting 
      process under-represented the iGTV by more than 10% or up to 4.2 cm3 when 
      compared to the iGTVcine. They suggest utilization of a MIP generated from the 
      full cine CT data set to ensure maximum inclusive tumor extent.
FAU - Zamora, David A
AU  - Zamora DA
AD  - Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 
      Houston, Texas 77030, USA.
FAU - Riegel, Adam C
AU  - Riegel AC
FAU - Sun, Xiaojun
AU  - Sun X
FAU - Balter, Peter
AU  - Balter P
FAU - Starkschall, George
AU  - Starkschall G
FAU - Mawlawi, Osama
AU  - Mawlawi O
FAU - Pan, Tinsu
AU  - Pan T
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Med Phys
JT  - Medical physics
JID - 0425746
SB  - IM
MH  - Aged
MH  - Aged, 80 and over
MH  - Automation
MH  - Female
MH  - Humans
MH  - Image Processing, Computer-Assisted
MH  - Male
MH  - Middle Aged
MH  - Motion
MH  - Neoplasms/diagnostic imaging/*pathology/*radiotherapy
MH  - Radiography, Thoracic/methods
MH  - Radiosurgery/*methods
MH  - Radiotherapy Planning, Computer-Assisted/*methods
MH  - Reproducibility of Results
MH  - Time Factors
MH  - Tomography, X-Ray Computed/*methods
PMC - PMC3810265
EDAT- 2010/12/17 06:00
MHDA- 2011/01/14 06:00
PMCR- 2011/11/01
CRDT- 2010/12/17 06:00
PHST- 2010/12/17 06:00 [entrez]
PHST- 2010/12/17 06:00 [pubmed]
PHST- 2011/01/14 06:00 [medline]
PHST- 2011/11/01 00:00 [pmc-release]
AID - 038011MPH [pii]
AID - 10.1118/1.3504605 [doi]
PST - ppublish
SO  - Med Phys. 2010 Nov;37(11):5811-20. doi: 10.1118/1.3504605.